spondee (n.)

"metrical foot consisting of two long syllables," late 14c., from Old French spondee (14c.), from Latin spondeus, from Greek spondeios (pous), the name of the meter originally used in chants accompanying libations, from spondē "solemn libation, a drink-offering," related to spendein "make a drink offering," from PIE root *spend- "to make an offering, perform a rite," hence "to engage oneself by a ritual act" (source also of Latin spondere "to engage oneself, promise," Hittite shipantahhi "I pour out a libation, I sacrifice"). Related: Spondaic.